1. Field of the Invention
The present invention relates generally to milling machines and methods for their use. More specifically, the present invention relates to a milling apparatus capable of milling a structural, machined component in situ within highly constrained physical operating parameters.
2. Description of the Prior Art
Structural components of modern machinery, especially major transportive craft such as aircraft and marine vehicles, are often prone to fatigue, structural failure and/or replacement. In this connection, one of the major limitations to aircraft service life is structural damage induced by service or stress loads encountered during aircraft use. Likewise, a major limitation on the service life of marine craft is corrosion and fatigue of selected areas of the ship structure. Both marine and aircraft undergo continuous retrofits and upgrades during their service life.
Traditional solutions to fatigue and structural failure have been to selectively repair or replace an affected component. Such repair and/or replacement has heretofore involved the disassembly and removal of the damaged component to a milling or machine shop. Such disassembly and removal, however, often represents an impractical and cost-prohibitive solution when the component forms a part of an air or marine craft which cannot be conveniently disassembled or where removal of the affected part is prohibitive due to weight or space constraints. Such considerations are also significant when retrofits or upgrades are attempted while the craft is still in service.
One solution to the above problems has been the development of portable milling machines which may, in a general sense, be utilized at the job site. Such portable milling machines are disclosed, for example, in U.S. Pat. No. 1,775,000 as issued to Sichel and U.S. Pat. No. 4,761,104 as issued to Hillestad.
Disadvantages associated with these milling machines, however, prevent their application to repair a structural member while it remains in contacting relation to the main body of the apparatus. Instead, portable apparatus such as those disclosed in Sichel and Hillestad merely provide for the milling operation to be performed in proximate relation to the craft itself and do not provide for in situ milling operations. Moreover, the cutting and milling movement employed by these apparatus does not allow their application to a physically restricted environment, such as within an aircraft wing or within the engine compartment of a marine vessel.